The wild winds that produced a dust storm in Borrego Springs Sunday also produced dust in El Centro. Photo by Jeff Alford.

San Diego’s western valleys were struck unusually hard Monday by thunderstorms, which accounted for most of the 280 lightning strikes recorded around the county.

The National Weather Service says moist, unstable air sparked lightning from Palomar to Escondido to Ramona, and along the international border, while also whipping up more than an inch of rain in and around the Palomar Mountains.

The La Jolla Amago Indian Reservation recorded 1.58 inches of rain, and Alpine got 1.35 inches. There were no reports of hail, and through early evening there had not been a repeat of the dust storm that covered Borrego Springs and El Centro on Sunday.

“It looks like we’ll have more thunderstorms on Tuesday, but they’ll be mostly confined to the mountain ridges and slopes and the desert,” said Brandt Maxwell, a weather service forecaster. “It doesn’t look like there will be any rain at all on Wednesday.”

Thunderstorms could be seen forming over the San Bernardino Mountains Monday from the southern end of Grandview Beach in San Diego County.
Gary Robbins

Thunderstorms could be seen forming over the San Bernardino Mountains Monday from the southern end of Grandview Beach in San Diego County.

Wildly unstable air produced 7,100 cloud-to-ground lightning strikes in southern Arizona on Sunday and generated winds that blew into the Borrego Springs area at 60 mph, producing a gritty, blinding dust storm that made it hard to drive or walk. The air also sparked intense thunderstorms and lighting on the eastern slopes of the San Diego Mountains.

Thunderstorm growth also was visible Monday from downtown San Diego.
Elaine Regan